that the hydrolysis of Zr(BH4)4•8NH3 in water can generate about 1067 mL/g pure hydrogen in 240 min at 298 K without release of diborane or ammonia impurity gases. With heat-assistance, the hydrogen generation rate can be significantly enhanced, and its activation energy was calculated to be 29.38 kJ/mol. The hydrolysis mechanism was clarified. The results demonstrate Zr(BH4)4•8NH3 may work as one promising
Zr(BH4)4•8NH3由于具有较高的氢密度和较低的脱氢温度,因此被认为是一种有前途的固态储氢材料。但是,氨的释放阻碍了其实际应用。为了进一步降低脱氢温度并抑制氨的释放,在这里我们研究了其水解过程以评估其氢生成性能。结果表明,Zr(BH4)4•8NH3在水中的水解在298 K下240分钟内可产生约1067 mL / g的纯氢,而不会释放出乙硼烷或氨杂质气体。借助热辅助,可以显着提高氢的生成速率,其活化能经计算为29.38 kJ / mol。阐明了水解机理。结果表明Zr(BH4)4·8NH3可能是一种有前途的制氢材料。
Ammonia borane modified zirconium borohydride octaammoniate with enhanced dehydrogenation properties
formation of the diammoniate of diborane for Zr(BH4)4⋅8 NH3–4 LiBH4, and the partial transfer of NH3 groups from Zr(BH4)4⋅8NH3 to Mg(BH4)2 for Zr(BH4)4⋅8 NH3–2 Mg(BH4)2, which result in balanced numbers of BH4 and NH3 groups and a more active Hδ+⋅⋅⋅−δH interaction. These advanced dehydrogenation properties make these two composites promising candidates as hydrogen‐storage materials.
The electronicstructure of epitaxial, predominantly single-crystalline thin films of zirconium diboride (ZrB2), a lattice-matching, conductive ceramic to GaN, grown on Si(111) was studied using angle-resolved ultraviolet photoelectron spectroscopy. The existence of Zr-derived surface states dispersing along the Γ¯-M¯ direction indicates a metallic character provided by a two-dimensional Zr-layer at
Low‐temperature deposition of zirconium and hafnium boride films by thermal decomposition of the metal borohydrides (<i>M</i>[BH<sub>4</sub>]<sub>4</sub>)
作者:A. L. Wayda、L. F. Schneemeyer、R. L. Opila
DOI:10.1063/1.100603
日期:1988.8
zirconium and hafnium borides have been deposited on various substrates by the low‐temperature (100–270 °C) thermal decomposition of Zr[BH4]4 and Hf[BH4]4. Auger electron spectroscopy of these films shows that their composition is ZrB2 and HfB2. The film surfaces are oxidized and slightly carbon contaminated. However, the bulk contains less than 1 at. % C or O. This synthesis is by far the lowest temperature